$re = '/^\s*\d+\s*$(?:\r?\n?)+^\s*([\d:,\.]+)\s*-->\s*([\d:,\.]+)\s*$(?:\r?\n?)+((?:.*(?:\r?\n?)?)*?)(?:\r\n|\r|\n|$)/';
$str = '
00:00:02,070 --> 00:00:8,572
(<i> explosion and number of members</i> )
(<i> inaudible radio chatter</i> )';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php